在使用tkx::open运行外部命令时检索stdout和stderr

Question

我在Perl (Tkx模块)中成功地运行了Tkx中的外部命令，而没有阻塞。

但是，我很难从stderr和stdout检索消息:对于大多数命令，变量$stdout和$stderr中什么都不存储。

我的密码里漏掉了什么？

谢谢

use Tkx;
use strict;
use Data::Dumper;

my ($stdout,$stderr);

my $mw = Tkx::widget->new(".");
my $button=$mw->new_ttk__button(-text => "Run", -command => [\&run_command, "systeminfo"]);
$button->g_grid(-column => 0, -row => 0);
my $text = $mw->new_tk__text(-width => 32, -height => 16);
$text->insert("end", "Test\n");
$text->g_grid(-column => 0, -row => 1);

Tkx::MainLoop();
print "STDOUT: $stdout\n\n","-"x24,"\nSTDERR: $stderr\n";


sub run_command {
    my $cmd = shift;
    my $fh = Tkx::open("| $cmd", 'r') or die "$!";
    Tkx::fconfigure($fh, -blocking => 0);
    $stdout.=Tkx::read($fh);
    eval { Tkx::close($fh); };
    $stderr.=$@ if ($@);

}

Answer 1

在Linux上，我可以使用Capture::Tiny获取外部命令的输出：

use strict;
use warnings;

use Capture::Tiny ();
use Tkx;

my ($stdout,$stderr);

my $mw = Tkx::widget->new(".");
my $button=$mw->new_ttk__button(-text => "Run", -command => [\&run_command, "echo aaa; eeee"]);
$button->g_grid(-column => 0, -row => 0);
my $text = $mw->new_tk__text(-width => 32, -height => 16);
$text->insert("end", "Test\n");
$text->g_grid(-column => 0, -row => 1);

Tkx::MainLoop();

sub run_command {
    my $cmd = shift;
    my ($stdout, $stderr, $exit) = Capture::Tiny::capture {
        system($cmd);
    };
    print "STDOUT: '$stdout'\n";
    print "STDERR: '$stderr'\n";
    print "Exit code: '$exit'\n";
}

输出：

STDOUT: 'aaa
'
STDERR: 'sh: 1: eeee: not found
'
Exit code: '32512'

编辑

为了避免阻塞GUI，请开发一个小包装脚本，例如：

$ cat wrapperl.pl
use strict;
use warnings;
use Capture::Tiny;

my $cmd = shift;

my ($stdout, $stderr, $exit) = Capture::Tiny::capture {
    system($cmd);
};
print "Child is waiting..\n";
sleep 2;
print "STDOUT: '$stdout'\n";
print "STDERR: '$stderr'\n";
print "Exit code: '$exit'\n";

然后使用：

sub run_command {
    my $cmd = shift;
    my $fh;
    print "Master: calling command..\n";
    system ("wrapper.pl \"$cmd\" &");
    print "Master: returning to Tkx::Mainloop..\n";
}

输出：

Master: calling command..
Master: returning to Tkx::Mainloop..
Child is waiting..
STDOUT: 'aaa
'
STDERR: 'sh: 1: eeee: not found
'
Exit code: '32512'